Stay ring for water turbines, pump turbines and pumps



Sept. 7, 1965 E. s. EDVARDSEN STAY RING FOR WATER TURBINES, PUMPTURBINES AND PUMPS Filed May '7, 1963 FEED SP/RAL.

TURB/NE S/MFT FIG. 3

1N VENTOR E064)? S/GFFED EDWRDSEN BY H0413 ,4 TTORNEYS United StatesPatent STAY RING FOR WATER TURBINES, PUMP TURBINES AND PUNEPS EdgarSigfred Edvardsen, Trollhattan, Sweden, assignor to Nydqvist & HolmAktieholag, Trollhattan, Sweden, a corporation of Sweden Filed May 7,1963, Ser. No. 278,708 Claims priority, application Sweden, May 7, 1962,5,104/ 62 1 Claim. (Cl. 253-26) The present invention relates to staywheels for water turbines, pump turbines and pumps, and particularly tothe form of the stay rings comprised in the stay wheels in a weldeddesign. The stay wheel, which consists of an upper and a lower stay ringand a number of intermediary stays, serves two purposes. For one thing,it comprises part of the water-ways, as it guides the water between thefeed spiral and the guide wheel and, for another thing, it absorbs theforces between the feed spiral, the head cover and the bottom ring.

It has previously been the usual practice to make the stay rings of caststeel, but owing to the development of Welding methods and the generaltendency towards larger units, welded designs have come more and moreinto the foreground. When stay rings were made of cast steel, thme weredesigned primarily with a view to obtaining an appropriate form, seenfrom a hydrodynamic point of View, and this had the consequence thatthey consist of double-bent elements. When changing to welded designs,the form used when the rings were made of cast steel has been retained,in general, which, however, involves certain disadvantages. Themanufacture of the double-bent elements comprised in conventional stayrings involves certain difiiculties and is very expensive, particularlywhen it is a question of large plate thicknesses, and the forceemanating from the feed spiral will be given considerable leverage instay rings made according to this design. This great leverage causes aconsiderable rolling moment for the stay ring, which results inincreased requirements for its dimensioning.

The above-mentioned disadvantages are avoided in the present invention,which relates to a stay ring of a welded design for water turbines, pumpturbines and pumps, and is characterized, in general, in that said stayring is constructed of a plane ring-formed plate, fitted at right anglesto the shaft of the unit, and a conical sweep, which connects saidring-formed plane plate to the feed spiral. The conical sweep shouldappropriately be inclined at such an angle that the forces emanatingfrom the feed spiral obtain the least possible torque lever and,further, the plate comprises a direct extension of the plate in the feedspiral. The conical sweep can possibly be supplemented with a thincovering plate, to obtain improved flow conditions and, finally, thestay ring can be made with stiiiening elements.

The invention will be described in more detail with reference to thedesigns shown in the attached drawing. In the drawing, FIGURE 1 shows inperspective, and with certain parts cut away, a stay wheel with stayrings made according to the present invention, and FIGURE 2, a sectionthrough the upper of these stay rings. FIGURE 3 shows a section of anupper stay ring according to a modified design of the present invention.

In FIGURES 1 and 2, 1 designates a plane, ring-formed plate, arranged atright angles to the shaft of the unit. A conical plate sweep 2 is weldedto this plane, ring- Patented Sept. 7, 1965 formed plate 1. The conicalsweep 2 is inclined at such an angle that the forces emanating from thefeed spiral (not shown in the figure) are given the least possibletorque lever. The seam between the two parts 1 and 2 should be machinedon the side directed downwards, so that a well rounded transition isobtained. The two plate elements 1 and 2 are comparatively easy tomanufacture, and together give a very stable stay ring even when theplates used have only moderate dimensions. This stay ring 12 is weldedto the upper part of the stays 3, the lower ends of which are connect-edto a stay ring 4-5 made in the same way.

Should the stay ring composed of the plane, ring-formed plate and theconical sweep not have a satisfactory form, seen from the point of viewof flow, it can be supplemented with a thin covering plate 8, whichguides the water in the way desired. As is shown in FIGURE 3, the plane,ring-formed plate 6 and the conical sweep 7 are rounded oli by thecovering plate 8. The stay 9 is fastened to the plate elements 6 and 7,and the only purpose of the covering plate 8 is to guide the water.Thus, it can be made of comparatively thin plate, whereby it will beeasy to manufacture.

Generally, the stay ring made of the plane, ring-formed plate and theconical sweep have entirely satisfactory mechanical stability, but if itshould be desired to further improve this stability, this can beachieved by means of stiifening elements of a simple geometrical form.Thus, it is shown in FIGURE 3 how the stay ring 67-8 has been providedwith a cylindrical stiiiener 10. In this case, the stay 9 protrudesthrough the conical sweep 7 and is firmly attached to the cylindricalstiffening ring 10.

I claim:

A stay ring structure for turbines and turbine pumps, said stay ringstructure comprising an annular plate, a plane sweep ring fixedlysecured along one edge to the outer periphery of said plate, said sweepring including a slot and extending outwardly of said plate at an anglein reference to the plane thereof, said sweep ring including at leastone stay and an annular stiffening member secured to said annular platecoaxially therewith and rising therefrom on the same side as said sweepring, said stay extending through said slot and being secured to saidstiffening member, and a flow-guide plate covering the outside of saidsweep ring and secured thereto along its edges and extending to theouter periphery of said annular plate, said flow-guide plate beingconcavely curved in reference to said sweep ring.

References Cited by the Examiner UNITED STATES PATENTS 1,896,644 2/ 33Pfau 253117 2,291,110 7/42 Sharp 253-122 2,524,390 10/50 Bach et al.230133 2,736,530 2/56 Koepke 253-422 X 2,808,227 10/57 Danel 2531173,051,441 8/62 Sproule 253-117 3,139,265 6/64 Lindquist 253117 FOREIGNPATENTS 876,230 5/53 Germany.

SAMUEL LEVINE, Primary Examiner.

JOSEPH H. BRANSON, JR., JULIUS E. WEST,

Examiners.

